The invention refers to a device for producing a friction joint of the type defined in the preamble of the annexed claim 1.
Such devices are used in different connections, e.g. for fitting different objects, such as bearing, gear wheels and the like to shafts or for interconnecting two shafts. The devices generally incorporate a sleeve with a taper surface, whereby the sleeve is intended to be displaced along a corresponding taper surface on a member enclosed in the sleeve or enclosing the sleeve, in order to be squeezed against said corresponding surface. The displacment is generally obtained by means of a nut arranged on a thread in the sleeve or on an adjacent member. The nut thereby has about the same radial dimensions as the sleeve, whereby large torsional moments are required at the tightening in order to overcome the friction resistance in threads and pressure surfaces of the nut. The taper angle of the taper surfaces must therefore be rather small in order to make sure that a desired radial pressure in the friction surfaces is obtained. This means that the joint generally will be self-braking, i.e. it will maintain its engagement also when its tightening nut has been loosened. Particular puller devices are therefore required for loosening the joint. Even if displacement members, which will give a sufficient axial force for allowing use of non-self-braking taper angles at the friction surfaces are earlier known, e.g. a number of axial screws arranged in threaded axial bores about a flange rigidly fitted to the element relative to which the sleeve is displaceable and with its end surfaces contacting one end surface of the sleeve, taper squeeze joints with large taper angles have not been used in a larger extent as such a joint would have a non-desirable radial extension.
The purpose of the present invention is to produce a friction joint, which operates according to the principle of a taper clamping sleeve, and which can be designed with a small radial extension without therefore being self-braking, whereby the joint can be easily loosened without particular aids.
This is according to the invention obtained with a device having the features defined in the accompanying claim 1.
A device according to the invention can be easily and cheaply manufactured and its use is uncomplicated. As the torque transferring ability of a small joint can be enlarged and the radial extension can be made small the device has a wide range of use.